Mise en évidence de la céphalosporinase plasmidique ACC-1 dans différentes entérobactéries (Klebsiella pneumoniae, Proteus mirabilis, Salmonella) isolées dans un hôpital tunisien (Sfax 1997–2000)

Abstract

Because a multiresistant K. pneumoniae outbreak detected in an intensive care unit of a parisian hospital, combined to the production of the plasmid-encoded cephalosporinase ACC-1, a probable importation via a patient was suggested from another country (Tunisia). The investigation was conducted to examine 35 clinical strains of enterobacteria resistant to ceftazidime without synergy towards Augmentin®. Other test of synergy with two inhibitors, BRL 42715, Ro 48-5545 was performed by diffusion method and deposit of 10 μg of inhibitor on disks containing ceftazidime, cefoxitin and cefotetan. Synergies were obtained suggesting a probable production of ACC-1 type among six isolates of K. pneumoniae (two), Proteus mirabilis (one) and Salmonella (three) issued from different units. The isoelectric focusing on gel revealed at least one band of β-lactamase activity at 7.8 but also demonstrated the simultaneous production of several probable β-lactamases including TEM-type, SHV-2 and ACC-1 among S. enterica ser. Livingstone. The PCR of the gene blaacc-1 was positive. The sequencing (1160 pb) of two products showed high identity (99–100%) with the gene blaacc-1 deposited in 1999. Finally the ACC-1 type reported in Tunisia was probably imported in France via a patient. Because a simultaneous synthesis of ESBL and ACC-1 type, its presence may be invisible and need more investigation.